1. The Ferns

2. Spore dispersal
Siphonosteles
Megaphylls
= the ferns

3. fern morphology: terminology
ferns have megaphylls, commonly called fronds
fern fronds typically have circinate vernation, expand by unrolling. Unexpanded fronds are often referred to as fiddleheads or croziers.
in most ferns the stem is an underground rhizome, although in some groups it can be erect and stocky
roots are adventitous and borne at the nodes
sporangia are usually abaxial on fronds and occur in clusters called sori
there are of two types of sporangia in the ferns:
EUSPORANGIA and LEPTOSPORANGIA

4. More terminology and frond dissection
twice- pinnate
Petiole or stipe
simple (entire)
once-pinnate
pinnate

5. Megaphyll

6. B C Siphonostele with nonoverlapping leaf gaps
Siphonosteles with overlapping leaf gaps

7. Eusporangia Leptosporangia
Sporangia sessile or short-stalked
Large sporangia (> 0.5 mm in diameter)
Sporangial walls several cells thick plus tapetum
Sporangia have no specialized dehiscence cells
Sporangia produce a large number of spores.
Sporangia on long, slender stalks
Small sporangia (< 0.1 mm in diameter)
Sporangial walls that are 1 cell thick plus tapetum
Sporangia usually have an annulus
Sporangia produce relatively few spores
(commonly 64)
Polypodiales
Ophioglossales
Marattiales

8. The Marattiales, an order of eusporangiate ferns

9. Vegetative morphology of the Marattiales
most species have short, upright, unbranched stems
large pinnately compound leaves
conspicuous swellings called pulvini occur at the bases of pinnae in many species
two persistent, clasping stipules occur at each leaf base
shoot borne roots are large, fleshy, and smooth

10. Members of the Marattiales have polycyclic siphonosteles

11. Reproductive morphology of the Marattiales
eusporangia are abaxial on the leaf in two rows along veins
eusporangia may be separate, unfused (Angiopteris spp.) or fused into a synangium (Marattia spp., Danaea spp.)
separate, unfused eusporangia
eusporangia fused into a synangium

12. Psaronius, a marattialean fern of the Late Carboniferous, had obconical stems

13. Section from distal end of stem below
Psaronius stems were clothed with a massive mantle of adventitous roots for stability
Section from distal end of stem below
Lower stem section with substantial root mantle

14. The Polypodiales, leptosporangiate ferns

15. Eusporangium leptosporangium
Spore dispersal
Eusporangium leptosporangium
Megaphylls

16. Examples of variously divided leaves
174 simple or entire
165 lobed
170 pinnatifid
166 & 171 pinnatisect
167 pinnate
159 bipinnate
162 bipinnatifid
Examples of variously divided leaves

17. B C dictyosteles Siphonostele with nonoverlapping leaf gaps
Siphonosteles with overlapping leaf gaps B C
dictyosteles

18. A dictyostele is the most specialized type of siphonostele seen in the Polypodiales
Leaf gaps